Lt. Col. Dave Grossman, author of the Pulitzer Prize-nominated book "On Killing," has some harsh truth for any American who believes that the war on terror and the war on crime are over.

"If you believe that things are getting better, you're in denial; you're a sheep," he told the mostly law enforcement audience assembled for his two-part keynote at the TREXPO East 2009 Conference and Expo.

Grossman's message at the annual trade show and conference held Aug. 18-21 at the Chantilly (Va.) Convention Center was that things are going to get worse before they get better. "We live in a dark and desperate time," he said.

Using examples from terror attacks around the world and active shooting incidents combined with criminal violence statistics, Grossman exhorted the TREXPO crowd to carry off duty and be ready at all times to take action to save lives.

The Beslan, Russia, school massacre was one of the focuses of Grossman's presentation. In graphic detail, he told the story of this atrocity as an example of the depravity of Islamist terrorists. "You imagine the most mind-numbing, gut-wrenching thing that you can think of and that's what they'll do," he stressed.

Grossman told the crowd that Osama Bin Laden has promised that Beslan is the future of America and that the frontline defense against such attacks is law enforcement. "Don't you think a cell of Islamist terrorists could kill more people than that idiot at Virginia Tech?" he asked.

Disputing conventional wisdom that America is now safe from Al-Qaeda attacks, Grossman argued that the only reason Americans haven't been attacked since 9/11 is that American forces have taken the war to Al-Qaeda. "The Koran tells them that they have to fight the jihad over there first," he explained. "But when we leave Afghanistan and Iraq that's when they will come after us here."

Stalking the stage like an old-time evangelist, Grossman used humor and biting comments to make his points. Speaking of conventional school security, he said, "Never call an unarmed man 'security.'" Speaking of concealed carry restrictions, he said, "We should call them 'unarmed victim zones.' Terrorists and active shooters and criminals, they seek out the weakest link. Statistics show that less than 20 percent of officers carry off duty. Do you want to be the weak link?"

In another biting comment, Grossman attacked officers who have time to go golfing but no time to go to the range. "Your hobby should provide survival skills. You know a golf course is just a deliberate and purposeful misuse of a perfectly good gun range. Let the sheep (unaware civilians) go graze at the golf course," he said and the crowd cheered.

On day two of his presentation, Grossman detailed the rise in violent crime and how statistics are being cooked. "We're fudging the figures, and they're still bad!" he said. "The only reason the murder rate is going down is the skill and effort of medical professionals," he added, arguing that a more important statistic than the murder rate is the attempted murder rate.

According to Grossman, the driving factor in the rise of violent crime worldwide is violent entertainment. He graphically detailed some of the more hideous aspects of video games such as "Grand Theft Auto" and "Postal 2" to make his point. "There is of course no simplistic single cause model, but take all of the other factors that influence crime rates and add violent visual imagery marketed to kids and you get the most violent generation ever," he said.

Grossman said that the only thing slowing the crime rate is the efforts of police officers. "You are the white blood cells protecting the body," he told the TREXPO crowd. "Thank you for taking 2.5 million of the most violent people in the history of the world off our streets. When you get home, I want you to look out over your community and know that you make a difference."

Listen to our podcast interview with Lt. Col. Dave Grossman recorded live at TREXPO East.